The rear wheel hub is the part that drives the rear wheel. The rider operates the pedals to rotate the chainwheel and the chain, and train drives the ratchet socket of the rear wheel hub. A sleeve extends through the ratchet socket which drives the rear wheel hub and the rear wheel. An axle extends through the sleeve and the size of the axle of the rear wheel hub can be replaced according to the need of the transmission force applied thereto. The two ends of the axle are connected with the bicycle frame so that the design for the sleeve is important for the bicycle.
The conventional rear wheel hub has a sleeve received therein and bearings are mounted to the sleeve and located between the sleeve and the hub. The hub is rotatable relative to the sleeve by the bearings. A ratchet socket is connected to one end of the sleeve and the hub is engaged with the ratchet ring of the ratchet socket. An end member is connected between one end of the sleeve and the hub. The other end member is located between the other end of the sleeve and the ratchet socket. An axle extends through the sleeve and two ends of the axle are connected with the dropouts of the bicycle frame.
The end member that is located away from the ratchet socket can be mounted exteriorly or interiorly.
One of the end members that is installed exteriorly is disclosed in Taiwan Patent Application No. 095108024 and discloses a hub and a freewheel which is connected to the hub and rotatable relative to the hub. One of the hub and the freewheel has an extension which extends radially therefrom and the other one of the hub and the freewheel has a securing member connected thereto. A seal member is secured in the securing member and a part of the seal member is in contact with the extension so as to form a sealing status between the hub and the freewheel.
One of the end members that is installed interiorly is disclosed in Taiwan Patent Application No. 0096200047 and discloses an axle which has a threaded section on the right end thereof. A hub has a passage and is mounted to the left end of the axle. Two bearings are located in two ends of the hub and mounted to the axle so that the hub is rotatable. A toothed ring is connected to the right end of the hub. At least two sockets are mounted to the right end of the axle with a bearing located between the sockets and the axle so that the sockets are rotatable. The socket has a ratchet ring which is installed to the right end of the hub and multiple movable ratchet teeth are located on the periphery of the socket. The ratchet teeth are engaged with the toothed ring. The socket has multiple axial engaging recesses and the sockets are engaged with the engaging recesses so that all of the sockets share a common axis. A right end member has a first threaded hole defined at the end that is located adjacent to the socket. The threaded section of the axle is connected to the first threaded hole and a second threaded hole is defined in the outside of the right end member. A threaded rod has a threaded portion which is threadedly connected to the second threaded hole.
For Taiwan Patent Application No. 095108024, the seal member is located between the one end of hub and the freewheel, and a locking nut is located between the first end of the hub and the first end of the axle. A seal member is located between the locking nut, the axle and the bearing. The second end of the hub and the second end of the axle has a second locking nut, and a second seal member is located between the hub, the locking nut and the bearing.
When removing the end member so as to replace different size of the axle, the locking nuts and the seal members on two ends of the hub have to be removed. However, the seal members are different to uninstalled and easily damaged. The cost will be too high.
For Taiwan Patent Application No. 0096200047, the left end member is connected to one end of the hub and a part of the left end member is located in one end of the axle. The right end member is connected to the other end of the hub and mounted to outside of the other end of the axle. The axle is connected to the first threaded hole of the right end member and a threaded part is connected to the second threaded hole of the right end member. By the different lengths of the engaging recesses, the distance between the axis of the rear wheel rim and the axis of the hub is maintained within a pre-set range. Therefore, when replacing the axle, the tension of the spokes does not need to be further adjusted.
When removing the end member, the right end member has to be first loosened and the left end member is then removed. The replacement of axle is not convenient for the users.
The present invention intends to provide a rear wheel hub assembly which improves the shortcomings of the conventional rear wheel hubs.